LVM是 Logical Volume Manager(邏輯卷管理)的簡寫，它是Linux環境下對磁盤分區進行管理的一種機制，它由Heinz Mauelshagen在Linux 2.4內核上實現，目前最新版本為：穩定版1.0.5，開發版 1.1.0-rc2，以及LVM2開發版。
LVM是建立在硬盤和分區之上的一個邏輯層，來提高磁盤分區管理的靈活性
可以看一下lvm的示意圖
每個磁盤可以分成多個分區，每個分區相當於一個pv，將pv化分成vg，在vg的基礎上創建邏輯分區lv，邏輯分區lv上創建操作系統的文件系統。注意boot需要直接建到物理分區上去的。
RedHat默認情況下是安裝lvm包的。
檢測操作系統是否安裝了lvm
[root@rac3 ~]# rpm -qa |grep lvm
system-config-lvm-1.1.4-1.3.el4
lvm2-2.02.42-5.el4
在支持熱插拔的服務器上安裝一塊硬盤。
先用partprobe掃描是否有新的磁盤在用fdisk -l查看磁盤，我安裝的磁盤就是最後一個
Disk /dev/sdg: 1073 MB, 1073741824 bytes
[root@rac3 ~]# partprobe
[root@rac3 ~]# fdisk -l
Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 140 1020127+ 8e Linux LVM
/dev/sda3 141 1305 9357862+ 8e Linux LVM
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 37 297171 83 Linux
/dev/sdb2 38 74 297202+ 83 Linux
/dev/sdb3 75 561 3911827+ 83 Linux
/dev/sdb4 562 1305 5976180 83 Linux
Disk /dev/sdc: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdc1 1 130 1044193+ 83 Linux
Disk /dev/sdd: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdd1 1 130 1044193+ 83 Linux
Disk /dev/sde: 4294 MB, 4294967296 bytes
255 heads, 63 sectors/track, 522 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sde1 1 522 4192933+ 83 Linux
Disk /dev/sdf: 4294 MB, 4294967296 bytes
255 heads, 63 sectors/track, 522 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdf1 1 522 4192933+ 8e Linux LVM
Disk /dev/sdg: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdg doesn't contain a valid partition table
1、先對磁盤進行分區格式化
[root@rac3 ~]# fdisk /dev/sdg
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-130, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-130, default 130):
Using default value 130
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
